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Humans needs to change course to stay within planetary boundaries

Scientists warn the 'Earth system' is deteriorating and people are to blame

A man waits to cross the road during heavy smog in Beijing. Scientists warn that while climate change is threatening to drive the Earth into a new state, other critical components of the planet’s system are also at risk.Photo: Kevin Frayer/Getty Images

Humans are the prime driver of the deteriorating “Earth System,” says an international research team that is calling for a change in trajectory.

“The only state of the planet that we know for certain can support contemporary human societies is now being destabilized,” says the report, published Thursday by the journal Science.

While climate change is threatening to drive the Earth into a new state, the report says several other critical components of the planet’s system are also at risk.

“Biogeochemical flows” that are key to food production and freshwater have been pushed beyond the safe boundary, as has loss of biodiversity due to species extinction.

The report paints a gloomy global picture that will be presented at the World Economic Forum later this month in Davos, Switzerland, giving innovators, thinkers and policy works plenty of challenges to tackle.

“It’s a great place to present these big unsolvable, difficult issues,” says co-author Elena Bennett, a natural resources specialist at McGill University. “These people can make things happen.”

The researchers’ “planetary dashboard” highlights what they are calling the “great acceleration” since 1950 that has made human activity the prime driver of change in the planet’s physical, chemical, biological and human processes.

An overpass in Beijing amid heavy smog. A new “planetary dashboard” by researchers highlights what they are calling the “great acceleration” since 1950 that has made human activity the prime driver of change in the planet’s physical, chemical, biological and human processes. [AFP/Getty Images]

The “human enterprise” has grown so dramatically that the relatively stable geological period known as the Holocene period that has supported society for 11,700 years “is now being destabilized,” the scientists report in Science.

Continuing on the current trajectory “could lead, with an uncomfortably high probability, to a very different state of the Earth System, one that is likely to be much less hospitable to the development of human societies,” says the Science report, that lays out nine “planetary boundaries” humans should not exceed.

“Respecting these boundaries would greatly reduce the risk that anthropogenic (human) activities could inadvertently drive the Earth System to a much less hospitable state.”

Lead author Will Steffen, of the Australian National University, says it is difficult to overestimate the scale and speed of change caused by human activities and industry.

“In a single lifetime humanity has become a planetary-scale geological force,” says Steffen. He heads a joint project between the International Geosphere-Biosphere Programme and the Stockholm Resilience Centre that shows the trajectories of Earth and human development are now tightly bound.

He and many of his colleagues say humans have become such a global force the current period in Earth’s history should be called the Anthropocene — the age of humans.

“After 1950 you can see that major Earth System changes became directly linked to changes largely related to the global economic system,” Steffen says in a statement released with the study Thursday. “This is a new phenomenon and indicates that humanity has a new responsibility at a global level for the planet.”

Bennett in Montreal notes how human changes to the planet’s biosphere, landscapes and biogeochemical flows are already pushing past the safe boundaries.

“That really indicates a danger zone, we are charting the great unknown of how the Earth system works,” Bennett said in an interview.

She says it’s important to lay out the “big picture” so people can focus on solutions.

“Reports like this are really important,” she says. “Even though they are a bit gloomy they are sounding the warning bell and saying ‘OK, now it’s the time.’ ”

Bennett studies problems with the planet’s biogeochemical cycle which are causing toxic algae blooms and “dead zones” in lakes and coastal areas.

Last summer, close to half a million residents of Toledo, Ohio, were told not to drink or bathe in the city’s tap water because of toxins released by algae in Lake Erie. The toxic algae were feasting on excess phosphorus and nitrogen running off over-fertilized fields and lawns, livestock pens and malfunctioning septic systems.

Bennett says such problems will get worse without a more comprehensive effort to curb run-off of phosphorus, which is a limited resource being dug out the ground and spread over fields.

“The obvious solution is recycling,” says Bennett, who would like to see a concerted global effort to recapture and recycle phosphorus from food and human wastes.

While innovators, policy-makers and governments all have roles to play in addressing the planetary threats, she says everyone can do their bit.

“Pick something and do it,” she says. “And don’t worry about it being a small thing.”

“Do what you can,” she says, be it using a reusable coffee mug instead of a paper one, driving your car less, or doing a better job recycling.

Margaret's work covering science - and science controversies - has taken her to the Arctic to see the effects of global warming, to Cape Canaveral for space launches and into Ottawa's paper labyrinth ... read moreto reveal how the Canadian government has been muzzling scientists.View author's profile